The story of Dr. Jekyll and Mr. Hyde is perhaps one of the most familiar tales in all of literature. In fact, it is so familiar that many people assume that the tale has been in existence for longer than it actually has been. It is also familiar because the terminology (that is, the names of Jekyll and Hyde) is now a part of our common language and can be found in any dictionary. In fact, many people who have never heard of the name Robert Louis Stevenson can offer a reasonably acceptable meaning for the term "Jekyll and Hyde," and their explanation would not vary far from those found in selected or random dictionary definitions such as:
1. "One who has quasi-schizophrenic, alternating phases of pleasantness and unpleasantness."
2. "A person having a split personality, one side of which is good and the other evil."
3. "This phrase refers to a person who alternates between charming demeanor and extremely unpleasant behavior."
In fact, the names of Jekyll and Hyde have even been used in alcoholism manuals to describe the behavior of a sober person who is kind and gentle but who unexpectedly changes into a vicious, cruel person when drunk. The contrast in the behavior of a drunk and sober person is therefore commonly referred to as the "Jekyll and Hyde Syndrome."
All of the general views or above definitions of a "Jekyll and Hyde" personality come almost entirely from the last two Chapters of the novel. Until then, the novel is presented as a closely knit mystery story.
